Drug allergies are an allergic reaction to medications. It’s when your body’s immune system overreacts to medications. Your body develops a sensitivity to one of the substances in the medication and “remembers” it as a harmful foreign invader, like bacteria or viruses. The next time you ingest that drug, your immune system releases antibodies to remove it from your body.
A drug allergy can be deadly. If you or a loved one have severe drug allergy symptoms, including swelling of your tongue or throat, trouble breathing, a fast heartbeat, lightheadedness or unconsciousness, you must act quickly:
Call 911 or your local emergency number.
Go to your nearest emergency room (ER) as soon as possible.
What are the signs and symptoms of a drug allergy?
An allergic reaction to medication usually begins within minutes after you take the drug. The symptoms and their severity can vary between people. Mild drug allergy symptoms may include:
Severe drug allergy symptoms may include anaphylaxis. Anaphylaxis is a serious allergic reaction that can be deadly without immediate treatment. Severe symptoms may include:
In rare instances, you may have an allergic reaction that slowly develops days or even weeks after taking a drug. The response can also last for days after you stop taking the medication. These reactions may include:
Your healthcare provider may recommend the following drug allergy treatments:
Stop taking the drug. Once the drug leaves your body, your symptoms should start to fade. If you’re taking the medication to treat a condition, your provider will prescribe another medicine that doesn’t cause an allergic reaction.
Antihistamines. Antihistamines block the effects of histamine in your body.
Corticosteroids. Corticosteroids are anti-inflammatory drugs that help reduce the production of chemicals that cause inflammation.
Bronchodilators. Bronchodilators are a type of medication that help relieve symptoms that affect your lungs.
Epinephrine auto-injector (EpiPen®). If you have severe medication allergies, your provider may prescribe this device. Epinephrine quickly reverses the symptoms of anaphylaxis. Your provider will explain when and how to use it.
Allergy desensitization. During allergy desensitization, a provider gives you small amounts of medications that contain the allergen. Your immune system will eventually develop a tolerance to the allergen. Your provider will gradually increase the dosage over hours or even days until your body can accept the drug without reacting.
How is a drug allergy diagnosed?
An allergist can diagnose a drug allergy. An allergist is a healthcare provider who specializes in diagnosing through tests and determining the best possible treatment.
Before conducting drug allergy tests, they’ll review your medical history and may ask some questions, including:
When did you first notice symptoms?
What are your symptoms?
How long did your symptoms last?
Did you take anything to help relieve your symptoms?
Did you need to go to a doctor’s office or to the hospital to receive treatment for your symptoms?